The use of prepared mixes has greatly simplified the task of preparing baked goods, particularly higher sugar/low water sweet baked goods such as brownies, cookies, some types of cakes, and the like. To prepare these mixes for use, the aqueous ingredients such as water, milk, or eggs are added to the mix and stirred to form a homogeneous batter. This batter is then baked to produce a final product. The use of such mixes avoids the problem of assembling the various ingredients, measuring the desired quantities, and mixing them in specified proportions.
Brownies are a very popular snack food and dessert, and it would be desirable to provide a mix whereby one could make a quality brownie quickly in a microwave oven. A quality brownie has a uniform texture, generally fudgey to cake-like. However, during microwave baking of brownie batter, dramatic textural irregularities often occur in the final cooked product. In some cases, the center of the brownie is almost raw, while the edges are unacceptably hard. These hard spots were found to be largely random along the edges and throughout the brownie, and specific to individual microwave ovens.
Maintaining constant brownie texture is more difficult in microwave brownies than in conventional brownies. It was found that this was due to edge heating and because of the uneven delivery of energy to the batter. "Hot spots" were also found to be a result of this uneven heating, and can be caused by interference patterns specific to every microwave oven. Hot spots often set up convection induced flow currents in microwave batter products. However, because of the high viscosity of brownie batter, there is little convection flow of batter, and little batter intermixing during microwave cooking. This lack of intermixing contributes to uneven heating and overly cooked areas near microwave oven hot spots.
Roudebush et al., U.S. Pat. No. 4,396,635, disclose a microwave cake mix wherein an emulsifier system is used to provide a cake mix which provides tender cakes with superior appearance. There is no disclosure in this patent of control of steam retention in a low moisture/high sugar baked good such as a brownie mix, nor is there recognition of steam retention in the system or of control of hard spots.